38 
tertian rings, especially in the tropics, pigment may 
be quite absent, (d) It is extremely easy even with 
the keenest attention to overlook young parasites, 
hence for diagnosis a stained specimen is the best. 
2. Large Parasites. —It is clear that the cell is 
occupied by a hyaline body, a parasite ; and the pig¬ 
ment often in motion, in some cases extremely fine, 
is obvious on careful examination. 
3. Crescents and Spherical Bodies (Fig. 9).—The 
former are, as in the stained specimen, characterized 
by their shape. They are distinct, fat, plump-looking 
bodies, unmistakable when once seen. They always 
have, besides, a central clump of distinct pigment. 
Stretching across between each end of the crescent is 
seen the curved edge of the red cell. The spherical 
bodies also possess this definite, easily seen pigment 
mass. 
4. Pigmented Leucocytes .—A body should not be 
diagnosed as a pigmented leucocyte unless it is first 
clearly made out that the body is a leucocyte, i.e ., 
possesses a distinct nucleus and cell substance. The 
pigment may consist of one or more black spicules or 
larger clumps evidently lying in the protoplasm. 
An epithelial cell is a flat-looking cell with a 
relatively small nucleus. Adherent skin pigment has 
not the fine acicular or granular character of melanin, 
and does not lie in the protoplasm (Fig. 7). 
Bodies in Fresh Films that may be Mistaken for 
Parasites 
1. Vacuoles. —Vacuoles and cracks have not the 
opaque look of parasites. The former cannot be 
focussed sharply, they c open out.’ Cracks have often 
